1. Field of the Invention
This invention relates to a grooving depth indicator for a highway grooving or milling machine, and particularly to a device for providing, at a location remote from the mechanism which determines the depth to which the highway has been cut, an indication of such depth. More specifically, this invention comprises a display device which is coupled by a tension cable to a mechanism which is employed to adjust the cutting depth of a highway grooving machine.
2. Description of the Prior Art
An exemplary prior art highway grooving machine is disclosed in Canadian Patent 994,145. The machine of Canadian patent 994,145 is provided with a milling or grooving depth indicator having a bar or pointer which will be displaced along a linear scale as a function of the vertical distance between the bottom of the cut being formed in the paving and the surface of the pavement ahead of the cutting tool. This bar is connected to a support wheel or some other part of the highway grooving machine which is employed to control the adjustment of the grooving depth. The indicator device shown in Canadian Patent 994,145 is characterized by a very long structure and cannot be satisfactorily integrated into the instrument panel of a highway grooving machine. In the apparatus shown in the Canadian Patent, the cutting depth is set by a hydraulic or electrical motor 12 in cooperation with a hydraulic cylinder 9, the motor 12 operating via a worm drive to adjust the position of a support wheel or wheels 10 for the cutting tools(s) 5. The Canadian Patent mentions, but does not disclose, means for providing, in the operator's cab, an indication of the position of the pointer 13c relative to the linear vertical-adjustment scale 13b. It is suggested, in the prior art, that such a telemetry device could include a Bowden cable or the like. Canadian Patent 994,145 also notes, however, that such telemetry systems have in the past proven to be complicated and costly and thus a simple mechanical pointer and linear scale has been the industry standard grooving depth indicator.